Average RV Gas Tank Size – Class A, B, & C with Examples

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Motorhomes are brilliant machines, but their owners should realize that they are not cheap to maintain. One of the costliest things associated with RVing is fuel.

If you’ve been interested in the fuel efficiency of motorhomes, you are in the right place. On this material, we are going to overview average gas tank sizes for class A, B, & C RVs with examples. Plus, we are going to give a couple of tips on saving fuel while RVing.

Average RV gas tank size – Class A, B, & C with examples

Average gas tank size for class A RVs

Let’s begin our comparison with class A RVs. Class A motorhomes tend to be the heaviest RVs out there, so naturally, they have the largest fuel tanks.

We’ve picked class A motorhomes from the following manufacturers – Jayco, Thor Motor Coach, Winnebago, Coachmen, and Forest River. We are going to overview over 30 class A motorhomes.

And while this may not be enough to get a comprehensive picture of gas tank sizes on the class A motorhome market, we think that we will get a general idea that is good enough.

Aside from the fuel capacity of the RVs, we’ve included their weights as well since weight is a very important factor when it comes to fuel efficiency.

Some of the included class A motorhomes also have diesel engines. In the names of such models, we included the word “diesel” so that you know what you are dealing with.

Now, let’s have a look at the figures of the class A motorhomes we’ve picked:

ModelGVWR, poundsFuel capacity, gallons
Embark Diesel32,000 – 36,320100
Alante16,000 – 18,00080
Precept20,500 – 24,000
Precept Prestige24,000
A.C.E16,000 – 20,50080
Hurricane18,000 – 22,000
Miramar22,000 – 24,000
Palazzo Diesel26,000 – 31,02090
Aria Diesel32,400 – 35,320100
Venetian Diesel38,700 – 44,700150
Tuscany Diesel38,600 – 46,000
Adventurer18,000 – 22,00080
Vista LX18,000 – 22,000
Intent16,000 – 18,000
Sunstar LX18,000 – 22,000
Horizon Diesel38,700 – 45,660100 – 150
Forza Diesel26,000 – 29,41090
Pursuit16,000 – 18,00080
Mirada18,000 – 22,000
Mirada Select22,000
Sportscoach SRS Diesel26,000 – 29,41090
Sportscoach RD Diesel32,000100
Berkshire Diesel32,250 – 33,350100
Berkshire XL Diesel36,400 – 38,320
Berkshire XLT Diesel44,320150
FR318,000 – 20,50080
Georgetown 3 Series GT316,000 – 20,500
Georgetown 5 Series GT520,500 – 22,000
Georgetown XL24,000
Legacy SR 340 Diesel29,410 – 30,50090


Well, as you can see, the range of fuel tank capacities is pretty wide among these class A motorhomes. In the examples above, the fuel capacity ranged from 80 to 150 gallons. And the most common fuel tank capacity observed on our chart is 80 gallons, which is characteristic of lighter class A motorhomes.

Since we’ve overviewed so many models from various manufacturers, we think that this range is going to be very indicative of other available class A motorhomes.

Now, you may have noticed that diesel class A motorhomes tend to be much heavier than their gas counterparts. 30-40 thousand pounds is a very common mark for them. Besides, their fuel capacity also tends to be higher, sometimes reaching 150 gallons.

Overall, it is considered that diesel motors are more efficient than gasoline motors, which is the thing that allows them to have not only heavier weight but also better towing capacity. Hence the increased fuel capacity in diesel RVs.

In fact, according to Southeast Financial, diesel engines can be 30% more efficient than their gas counterparts.

So we’ve established that class A motorhomes usually have between 80-150-gallon fuel tanks, but what about fuel efficiency? Well, class A motorhomes tend to be the least fuel efficient among all types of RVs due to their heavier weight.

According to the same report by Southeast Financial, the MPG (miles per gallon) for class A motorhomes tends to be between 8-13. For comparison, class B motorhomes tend to have the highest MPG – 18-20 – while class Cs provide moderate figures from 10 to 15 MPG.

There are plenty of factors that may be in play here, but the most important one is the higher weight of class A motorhomes, as we mentioned above. At a given fuel capacity, the heavier the motorhome, the less fuel-efficient it is going to be.

For example, suppose you have 2 options to choose from – a larger 20,000- and a smaller 16,000-pound class A motorhomes, with both having the same fuel capacity. Needless to say, the larger motorhome is going to be more comfortable, but it is going to be less fuel-efficient due to the extra 4,000 pounds it has.

If your goal is to save as much money on fuel as possible, you will want to opt for the lighter motorhome. But if you don’t really care about fuel efficiency and would rather have more interior room in your RV, then a larger and heavier motorhome would be better, but with the tradeoff of worse fuel efficiency.

This rule also applies to other motorhome classes. Lighter class Bs and Cs are less comfortable than class As, but they are noticeably more fuel-efficient.

That’s it for class A motorhomes. Let’s move on to class B RVs.

Average gas tank size for class B RVs

When choosing class B motorhomes, we followed the same logic as with class A motorhomes. We have fewer class B motorhomes on our list, but we still should have enough data for a good general idea of gas tank sizes in class B RVs.

We’ve picked class B motorhomes from Winnebago, Coachmen, American Coach, and Airstream.

ModelGVWR, poundsFuel capacity, gallons
Revel Diesel8,550
Galleria Diesel11,03024
American Patriot Cruiser Diesel11,03024.5
American Patriot Diesel8,550 – 11,030
Atlas Diesel11,03026.4
Interstate Lounge EXT Diesel24.5
Interstate Grand Tour EXT Diesel
Tommy Bahama Interstate Diesel
Interstate Nineteen Diesel8,550


Class B motorhomes are the lightest among motorhome classes, with their weight usually being around 10,000 pounds. Generally, class B motorhomes weight between 10,360 and 11,030 pounds. This is because class B motorhomes are mostly based on the Mercedes-Benz Sprinter chassis. And some class B RVs are based on shorter and lighter variants of the Sprinter chassis.

This also explains why the fuel capacity is very similar in all the models we’ve picked. About 25 gallons may seem very little after the 80-150 gallons of class A motorhomes, but given the weight of class B RVs, 25 gallons is very good fuel capacity.

As we’ve mentioned above, the MPG of class B motorhomes usually is 18-20, which is the highest among all motorhome types. And this clearly shows that 25 gallons in class B motorhomes are quite enough.

What we’ve described in our class A motorhome section applies to class B RVs as well. Namely, at a given fuel capacity, a lighter motorhome is going to be more efficient. Class B motorhomes are quite efficient by themselves, but you could get better efficiency by opting for a lighter model.

Average gas tank size for class C RVs

Lastly, we have class C motorhomes, which are somewhere in between class A and B motorhomes. Things are more interesting with class C motorhomes than you may think though.

We’ve selected class C motorhomes from Jayco, Thor Motor Coach, Winnebago, and Coachmen.

ModelGVWR, poundsFuel capacity, gallons
Redhawk SE14,20057
Greyhawk Prestige
Melbourne Diesel11,30026.4
Melbourne Prestige Diesel
Chateau12,300 – 12,50055 – 57
Four Winds
Minnie Winnie11,500 – 14,50055
Spirit11,500 – 14,50055
Fuse Diesel10,36025
Concord14,200 – 14,50055 – 57
Freelander10,360 – 14,50025 – 57
Cross Trek10,36025
Prism Diesel11,03026


As you can see from the table above, class C motorhomes tend to have fuel capacities from about 25 to 57 gallons, which is indeed between class B and Class A motorhomes. There’s even the 100-gallon Seneca with its 29,000-pound weight, but it is more of an exception among class C motorhomes.

Now, you may be thinking that 25 gallons isn’t much, but if you look at the weight of the models with 25-gallon tanks, you will realize that they are no less efficient than comparable class B motorhomes. That’s because class C motorhomes with 25-gallon tanks are built on the Mercedes-Benz Sprinter chassis, the same one used in class B motorhomes.

As a result, lighter class C motorhomes built on the Sprinter chassis are going to have a close, if not identical fuel efficiency to class B motorhomes.

The heavier motorhomes that weigh around 14,000 pounds have bigger 55-57-gallon fuel tanks but have lower fuel efficiency – around 10 and 15 MPG, as we’ve established above. However, larger class C RVs like the Jayco Seneca are going to be closer to class A motorhomes in terms of fuel efficiency.

Now that we’ve established the gas tank sizes and mileages in motorhomes, let’s find out how to increase fuel efficiency in your RV.

How to calculate gas mileage?

Average RV Gas Tank Size

First off, you will need to calculate the current gas mileage – miles per gallon (MPG) – of your RV.

Manufacturers usually do provide estimates on gas mileage of their motorhomes, but in reality, the numbers that you are getting may vary significantly either towards the better or the worse. This is because there are a variety of factors that impact fuel efficiency, which we will examine a little later.

Before actually trying to optimize your RV’s fuel usage, you need to find out its gas mileage in its current state. This is necessary so that you have a point of reference to make comparisons with.

Unfortunately, there isn’t a universal formula that would allow you to measure your RV’s gas mileage with just a calculator. Gas mileage is more of a statistical measure, and you actually do need to do some driving in order to find out your RV’s MPG.

So, here’s what you should do in order to measure your RV’s gas mileage:

  • Fill up the RV’s gas tank to the full.
  • Record the master odometer mileage. If the RV’s odometer can be reset, you may go ahead and reset it, but only if you don’t need the old data.
  • Drive the RV as you would normally, without trying to optimize fuel. Let your gas tank deplete to at least its half.
  • Fill your gas tank all the way again. Record the amount of gas you refilled.
  • Record the elapsed mileage of your trip. If you have reset your odometer before the trip, just record the number that is displayed on it. Otherwise, subtract the pre-trip reading from the current one.
  • Divide the miles traveled by the number of gallons it took to fully refill your tank. This is the formula for gas mileage – MPG = miles driven/gallons used. For example, if you’ve traveled 300 miles and refilled 15 gallons of fuel, the MPG would be 300/15 = 20 miles per gallon. The higher this number, the more efficient your RV is.
  • If you use kilometers and liters, the procedure will be exactly the same.

In case you also want to find out your rate of gas per mile, follow these steps:

  • Measure your MPG.
  • Take the average price that you paid per gallon during your trip.
  • Divide the average price per gallon by the MPG of your RV. This is the formula for calculating – price per mile = average price per gallon/MPG.

The rate of gas per mile also is a very useful metric that you could use in order to optimize your RV’s fuel consumption.

So, after you have a point of reference, you will be able to assess the effect of fuel optimizations on your gas mileage.

Now, let’s have a look at the things that you could do to increase your RV’s fuel efficiency.

How to increase your RV’s fuel efficiency?

Take care of your RV

The first thing you could do in order to save money on fuel is taking care of your RV. Most importantly, take care of your RV’s engine. Without diving too much into details, you should know that a bad engine that isn’t taken care of will be less efficient than you may expect.

For some perspective, you can achieve an average of 4% increase in fuel efficiency after fixing a vehicle that is out of tune or has failed an emission test. Depending on the RV’s condition, the effects may be much more dramatic, sometimes reaching 50-60% and even more.

Maintain proper tire pressure

Newbies probably don’t know about this, but maintaining proper tire pressure is crucial for saving fuel. The effect of tire pressure on fuel economy is quite significant – according to the data of several studies, of the effect of tire pressure on fuel economy is expected to be 0.308% for every 1% increase in average tire pressure.

The referenced paper cites a number of reports, in which the predicted increase in % of MPG/psi ranged from 0.1 up to 0.6%, with 0.308% being their average. Even a 0.1% effect is going to make a difference – in tires with 80% of proper tire pressure, the fuel economy loss would probably be 2%, which is going to result in huge fuel costs in the long term.

If we take 0.6% as the basis of calculations, then at 80% of proper tire pressure, losses would be equal to 12%. So, as you can see, merely maintaining improper tire pressure can result in significant costs over long time periods.

Now, we’ve mentioned a thing called proper tire pressure. In reality, you don’t want to inflate your tires to maximum pressure since it’s also inefficient. Instead, your RV’s tires need to be inflated only at the recommended pressure.

The proper tire pressure is usually indicated in the RV’s owner’s manual and/or on a sticker in the glove box or at the driver’s side door jamb.

Use recommended grade motor oil

It is also important that you use proper grade motor oil with your RV. Again, you should be able to find motor oil recommendations in your RV’s owner’s manual.

Overall, gas mileage improvements from using proper grade motor oil can reach 1-2%. As the cited paper claims, using 10W-30 motor oil in a 5W-30 engine can lower gas mileage by about 1-2%. And using 5W-30 motor oil in a 5W-20 engine is going to lower your gas mileage by around 1-1.5%.

These are small numbers, but fuel costs will add up and make a huge sum over a long period of time.

Reduce the weight the RV carries

Needless to say, the heavier your RV, the less fuel efficient it is going to be.

A 100-pound increase in your vehicle’s weight could reduce your gas mileage by around 1%, depending on the percentage of the added weight in relation to the vehicle’s weight. The smaller the vehicle, the greater the negative effect of extra weight is, so RVs are more efficient in this regard.

Try not to carry unnecessary stuff in the RV, especially if it is heavy. While the effect of extra pounds isn’t as big in heavy RVs, you should nonetheless pay attention to every pound of weight you have in your RV.

Avoid hauling cargo on the RV’s roof

Hauling cargo on the roof of your RV is another thing that you may want to avoid, if possible. And it’s not only about weight efficiency – it still plays a role, but with on-roof cargo, another problem is aerodynamic drag (wind resistance).

According to research, fuel economy penalties with rooftop cargo on a compact sedan are 10-25% at interstate speeds, 6-17% at highway speeds, and 2-8% in city driving. These are quite serious numbers, mind you, though fuel efficiency penalties will be lower with RVs.

Like it is with vehicle weight, larger vehicles are less susceptible to fuel efficiency loss since they are not too aerodynamically efficient in the first place. On the other hand, the size of the rooftop cargo also plays a role – the larger it is, the higher the fuel efficiency penalties will be.

In the end, if possible, avoid hauling cargo on your RV’s roof. Instead, store it inside the RV.

Drive at an efficient speed

Aggressive driving – rapid acceleration and braking, as well as speeding – is very inefficient. In light-duty vehicles, aggressive driving results in 10-40% fuel efficiency reduction in stop-and-go traffic and around 15-30% at highway speeds.

Driving at more reasonable speeds is thus a good idea if you are concerned with fuel efficiency.

A thing that may also help you with increasing your gas mileage is using driver feedback devices.

One research paper suggests that feedback devices help the average driver increase their fuel economy by 3%. Those who use feedback devices specifically to save fuel can achieve around 10% improvements in gas mileage.

The optimum driving speed for each vehicle is going to be different, but generally, fuel efficiency decreases rapidly at speeds over 50 mph. You may assume that each extra 5 mph of speed above 50 mph is going to cost you an extra $0.20 per gallon of fuel.

Avoid unnecessary idling

Aggressive driving has a negative effect on fuel economy, but so does excessive idling.

There is a persistent point of view based on decades-old engine technology that starting an engine consumes more fuel than when idling for a short time. This has been more or less true with low compression ratios, carburetors, non-heated oxygen sensors, and rudimentary fuel injectors, but not anymore.

Modern engines with their sophisticated technologies allow for significantly enhanced fuel control. As a result, an approximate of 10 seconds worth of idling fuel is used for each start. Thus, it would be worth keeping the engine running idle only if the idling didn’t exceed 10 seconds. Otherwise, the engine should be shut down in order to save fuel.

Make corrections and recheck

After making corrections to your RV or driving style, again calculate your RV’s MPG. Keep in mind that it won’t necessarily increase after you fix your engine or change your driving style – it may be that there aren’t problems with your RV’s fuel efficiency to begin with.

All in all, fuel efficiency is a very serious topic. There are hundreds of dollars that you can potentially save by just following the tips above. And if you have never paid attention to your RV’s fuel efficiency, you should start doing so from now on.



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